I am building an application where the user can generate tables on the fly. The description of these tables are stored at the back-end.

I needed to generate models from these descriptions and be able to use data grid objects to manipulate the data (crud operations).

I have looked in this forum for a solution to this as I had realized that the current ExtJS 4 does not support adding fields dynamically to a model or a store, .. but I had no luck finding something that works for what I needed (in Extjs4).

Anyways, I came up with a solution using 'eval' that does exactly what I wanted , .. and I wanted to share it with you.

Hello,I appreciate very much if sombody could tell me how should I add a renderer function call in the columns definition.

My way is to extend `Ext.grid.column.Column` with anything i need: renderer, filters, onTriggerClick(ExtJS 4), complex items, etc. Then to set that `xtype` in columns definition sent with `metaData` to reconfigure model/grid.